Reenforcing bar for concrete



C. 5. BOARDMAN REENFORCING BAR. FOR CONCRETE July 12, 1927.

Original Filed Dec. 15. ,1921 2 Sheets-Sheet 1- IN VEN TOR A TTORNE YPatented July 12, 1927.

'- UNITED STATES CHARLES S. BOARDMAN, OFlBUFFALO, NEW YORK.

nnnuronome BAR r03. conoien'rn.

Application filed December 15, 1921, Serial No. 522,499. RenewedDecember 8, 1926.

-This invention relates to reenforcing bars for concrete and is designedparticularly with the object of producing an improved bar which may besuccessfully rolled and .6 which will possess additional and importantadvantages over the types of bars as heretofore used for concretereenforcing.

An important and characteristic feature of my improved reenforcing baris that it is composed of alternating portions or unit lengths ofdissimilar cross-section wherein the alternation of cross-sectionaffords the means for mechanical bonding entirely or to a substantialdegree. My present invention further contemplates the production of abar employing alternations of unit lengths of standard plaincross-section offering additional and important'advantages as willhereinafter appear. v

In the appended drawings wherein there are illustrated approvedembodiments of the present invention, similar reference characters areemployed to denote the corresponding parts in the several views wherein:a

Fig. 1 is'a side elevation of a bar embodying features of my invention.Fig. 2 is a. cross-sectional view on line 22 thereof. Fig. 3 is asimilar cross-section taken on line 33. I i

Fig. 4 is a view in side elevation illustrating a modified embodiment ofmy improvements. v

Fig. 5 is a cross-section thereof on line 55.

Fig. 6 is a similar cross-section taken on line 66 thereof. I

' Fig. 7 is a view in side elevation illustrating a further modified barmade in accordance with the present invention.

Fig. 8 is a cross-sectional view thereof on line 8-8.

Fig. 9 is a cross-sectional view taken on line 9-9.

Fig. 10 is a side el'evational view of a further modification. V 1

"Figs. 11 and 12 are respectively cross-sections thereof taken on lines1111 and 1212.

Fig. 13 shows inside elevation another modified embodiment of" myinvention.

Figs. 14; and 15ers cross-sectional views thereof taken on lines l414and 15-15 respectively.

My present invention in its simplest expression contemplates theproduction of a rolled bar of what may be termed multiple cross-sectionin that it is composed of suc-e each possessing specific advantages andmeeting individual favor. My improved bar is specially designed topossess the important advantages of both types of bar, the respectivesections of which it combines.

It furthermore offers the additional and important advantage of beingadapted for use therewith of accessories designed for use with eithertype of cross-section of bar such as the various forms of supports andfastenings, for instance the commonly employed wire stamped metalfastenings used for holding the reenforcing bars in accurate position.As is readily appreciated my improved bar permits of the use offastenings designed for either of the two cross-sections by assemblingwith either the square or round portions of the bar in the specificembodiment as illustrated- The length of the respective divisions orunit-lengths of the bar having uniform cross-section may be proportionedas desired, but preferably the length of the respective units may be oneor more diameters of the bar and desirablyinay approximate threediameters of the bar, as illustrated.

The combined 'crosssect-ions as shown.

consisting of alternating unit-lengths of round and squarecross-sectional contour are preferred both for the reason that thesecross-sections are to a large degree stand ill ardiaed and owing to thecircumstance that these related cross-sections IlVG approximately thegreatest difference in cross-section, Col-respondinnly. in the describedtype of bar wherein the full mechanical bonding results from the changein crossseotion the prescribed cross-sections produce abar which wouldbe more ditticult to pull out of concrete than most any other twocross-scctions that may be selected.

The cross-sectional areas of the respective unit bar lengths ofdissimilar cro s section desirably are equal thereby prodncin; a bar ofSubstantially unit'orm properties as to strength. tension-a1 values.bending: moment. etc.. throughout its length. At the junctions of thetwo different cross-sections of bar additional metal i'iiiay be providedin the form of small fillets l. and 5 to compromise the respectivesections over the junction area 3 and gradually reducing the extendedportion of the bar length of one cross-section to the adjacent surfaceof the bar length ot dissimilar cross section. As exemplified in thellltlFilL'flilOl'lS the fillets at are reducing exten sions of theextendii'ig square or angular portions of the bar and the tillets aresimilarly associated with the extending round portions and converge withthe squared surfaces.

The multiple bar construction as illustrated in Figure 1 essentially adeformed bar without corrugations or bosses, requiring but slightadditional metal at each change t cross-sectioi'i in the form oi thedescribed fillets. There is thus produced a concrete reentorcing barhaving a sul'istantially uniform area. of cross section providing formechani- -al bonding: without additional metal in the 'lorm ot' boss sand without deformation of thebarsurhlce.

In many of the reeni'orcimr bars previously designed and some of whichhave been rolled. the change in cross-section to produce theitletormations for mechanical bonding has been brought about byrolling); the leader he f and making the reduction in the cm sscetion bylocal indentures into the bar in the final pass of rolling. This type ofbar has been proven to be structurally weak. First, the fibres of themetal in this change of cros, section have been sheared and destroyed inthe reduced area of the bar. this reduction having been made in thefinishing process when the bar has reached a low rolling temperature andhas afi'ected the metal by compressing the fibres. intensifying thestructure and melting a brittle bar.

This objectional local deiormation ot' the bar surface is avoided in myimproved de sign of bar which tormatively allows oi the bar being;rolled to completion without imwiring the physical structure of thesteel. In my design of bar the changeof crosssection is made by allowingthe original metal to flow in the form of the bar and men bar ot myimproved desiei'i moditicd to incor .)(n'ate therewith bosses or annularshoulders ti i'm'nicd at the junction o'i the dissimilar unit lengthso't bar in lieu of the lillets ot the first (llflt'lOSlll'G. In thismodified Form the bo ses are formed to be non-projecting; beyond thegreatest diai'nelter ot the plain bar sections.

Figs. (5 to 8 show a ilurther modified bar of this design with thebosses t3 oi" a diameter exceedingthe greatest projection oi either barlei'ipgth from the center of the bar.

a bar ot comparativcly greater holding power in concrete is obtained by1 bar havingrthesc cros sections alternating at regular intervals. withthe additional metal in bosses placed at the junction of these twodill'ercnt cross-sections. making these bosses of larger diameter andusing the additional metal only which would he used in the two or morecorrugations oil the now ez ein e' recnlkircing bars.

in Figs. 10 to a suitable modification in the construction of my imuoved bar is illustrated to adapt it to be rolled by ungearcd rolls withcorresponrlinc cormnercial ad.- vantage.

The torn'i oi? bar, an illustrated in Figs. ll) to 12 inclusive. may beobtained by a rolling operation employing roll:-; which are not; gearedto accurately rotate Ill unison. This form ot bar is gl'el erallysimilar to the illustration oi Fig. 3. but wherein. in, adilition, thereproridci'l and integrally rolled on the bar at o iposite sides alongitudinally extending: boss or rib T to which the boss ti areconnected in continuity with their maximum diameters in the camecylimlrical plane oi of corresponding projection.

The provision oi the lzmgitudinal llll-l i'. which in the rolling;operation will, occur at: the division oil the rolls. allows oi the barbeing termed by the riu pectii'e rolls with unsynnuetrical di positionor relative posh tioninp; of the ho. or auction a ea-a upon therespective haires oi the bar. The bar produced may. therefore.correjptuul to the example illustrated in l i 'il?) to it) which isprovided with the into longitudinal rib 7 and (he boL-ses upon theopposite rides of the center of the be r in dissimilar or nonsynnnetrical arrangement. .ls will be noted this bar is or acharacterembodying the nu portant features of my invention in that it isa multiple bar structure conuiosell ot alternately arranged unit lengthsof dissimilar ill) readable upon the-cross-sectional contour of one sideof the baronl'y for as illustrated in the cross-sectional views of Figs.l t-and 15 the resulting full cross-sectional contour is substantiallyuniform but with the dissimilar surfaces reversely arranged. Theinvention may therefore be defined with particular reference tothisniodification as comprising a bar of the multiple characteristicsdescribed having longitudinally successive elongated plane parallelsurfaces the alternate surfaces being provided by forming the bar ofdissimilar and'plain cross-sectional con-- tour. 1 T

The described longitudinal rib 7 in addi tion to its function inconnection with the rolling operation adds to the tensile strength ofthe bar and furnishes support and anchorage for the transverse ribs bothduring the rolling operation and in the finished bar.

I have thus produced an improved bar combining the characteristics andadvantages of both the plain round and plain square cross-sections andproviding for mechanical bonding in a more economical manner andavoiding the important objections to deformed types of bars asheretofore produced. In addition to the described advantages it may beadded that my improved bar will be as effective against twisting inconcrete as the commercial cold twisted square bars and, furthermore, byreason of its being a multiple of what may be termed plain sec tions,there are no objectionable depressions therein which would hold waterwith danger of corrosion of bars in storage. Also, as described there isprovision made for substantially increasing the mechanical bondoperatively occurring between the concrete and the bar, by reason ofthechange of crosssection, considered with relation to the dissimilarcross-sections of uniform'cross-sectional area, so that a substantialdegree of bonding is effected without additional metal.

In connection with the specific embodiment of my invention as hereillustrated an additional commercial advantage may be obtained withrelation to the customary practice of rolling square and round barsections of sizes or diameters giving two sets of correspondinglydifferent areas related to the respective sections. While my bar can berolled to include all of these areas so that it can be applied ininstallations based upon the round bar or square bar calculations, itoffers an instrumentality for compromising the sections with relation tothe sizes or bonding areas allowing for the elimination of half thenumber of sizes of the respective sections and with a correspondingreduction in rolls required thereby reducing the cost of manufacture.

While I have illustrated and described typical embodiments of thefeatures'ofmy present invention it will be understood that the same maybe otherwlseand further modified without departing from the scopethereof and it is therefore intended that all.

matterherein shall be interpreted as illustrative and not 111 a limitingsense. In this connection it may be added by way of further example thatthe longitudinal rib type bar, as illustrated in, Figs. 10 to 15,conformlng generally in other respects to a non-projecting boss designof Fig. 4 may in similar manner be incorporated with the type of barillustrated in Fig. 7 having the bosses in projecting arrangement.

The term plane in the foregoing description and in the appended claimsis employed as generally descriptive of the regular or uninterruptedsurfaces of both the unit lengths of square and round cross-section inthat the surface of the latter is in a cylindrical plane.

Having described my invention I claim:

1. A'multiple section reenforcing bar of the character describedcomprising a bar having alternating unit lengths of dissimilarcross-section and formed with bosses positioned at the junction of therespective unit lengths substantially as described.

2. A reenforcing bar of the character de scribed comprising a bar havingalternating lengths of dissimilar cross-sectional contour, the change ofcross-section providing for mechanical bonding, each unit length ofdissimilar section having plane longitudinal parallel surfaces and saidbar being formed with additional metal at the junction of theunit-lengths providing junction areas of increased cross-section; Y

3. A reenforcing bar of the character described comprising a bar havingalternating unit lengths of dissimilar symmetrical cross- 7 sectionalcontour, and having longitudinally parallel surfaces, each unit lengthextending longitudinally of the bar for a distance corresponding to atleast the diameter thereof and said bar being provided" with bossespositioned at the unction of the unit lengths substantially as,described.

4. A multiple section reenforcing bar of the character describedcomprising a bar having longitudinally successive elongated planeparallel surfaces, the alternate surfaces being provided by forming thebar ofv dissimilar, symmetrical cross-sectional con 7 tour and havingbosses formed at the junction of said successive surfaces, substantiallyas described.

5. A multiple section reenforcing bar comprising a bar havingalternating unit lengths of plam square and plam round cross-sec- (i. A1111111 iple section reen'forcing bur c0111- prisinp; a bar havingalternating unit; length of plain square and plain round cross-sew (ion,The length of the respective units extending longitudinally of the bar adistance greater 1112111 the diameter of the bail, and said respectiveunits having substantially equal cross-seetiol'iui are-n5, bosses formedon the her and positioned at the change of cross-section and providingjunction por- 10 tions of increased err ss-seefionu1 area.

.Ln testimony whereof I have signed my name to this specification.

CHARLES 1"}. BOARDMAN.

